Data processing method and apparatus, recording medium, reproducing method and apparatus using the same method

ABSTRACT

A burst error-correcting capability is largely improved. At least the even-number row and at least the odd-number row of the data block which is a set of data sectors are separated. An outer parity is created for each column and an inner parity is created for each row. Then, the outer parity is scattered with respect to each of the sectors of the data block to be interleaved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. §120 andis a divisional of U.S. application Ser. No. 10/765,848, filed Jan. 29,2004, now U.S. Pat. No. 7,124,345 which is a divisional application ofSer. No. 09/804,242, filed Mar. 13, 2001, now U.S. Pat. No. 6,718,510,issued on Apr. 6, 2004, and is based upon and claims the benefit ofpriority from the prior Japanese Patent Application No. 2000-255463,filed Aug. 25, 2000, the entire contents of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to a data processing method and apparatus,and a recording medium for an error-correcting product code favorablefor use in the recording and transmission of digital data.

More particularly, the present invention relates to a data processingsystem using an error-correcting product code which comprises anerror-correcting outer parity and an error-correcting inner parity whichare effective in the case where information data is recorded on aplurality kinds of recording media particularly having a largelydifferent recording density. Here, particularly, in a method for formingthe outer parity, a PO series creation by n sets of data itemsaggregated by n rows is used. Consequently, even when theerror-correcting product code block is recorded on a recording medium inan order of data transmission without carrying out data interleaveprocess; the capability of coping with the defect is largely improved.

In a system in which digital data is recorded on an optical disk bybytes (one byte is equal to eight bits) or digital data is transmittedto a transmission channel, a Reed-Solomon error-correcting product codeblock is constructed to process data. That is, (M.times.N) bytes of datais arranged in a matrix containing an M rows.times.N columns. Then, PObytes error-correcting word is added to each column of M bytesinformation portion. Then, PI bytes of error-correcting words are addedto each row of N bytes information portion. Then, (M+Po)rows.times.(N+Pi) columns Reed-Solomon error-correcting product codeblock is constructed. Then, this Reed-Solomon error-correcting productcode block is either recorded on a recording medium or transmitted to atransmission channel. The error-correcting processing portion on theinformation reproduction side of the recording medium and the receivingside of the transmission channel are capable of correcting random errorsand burst errors on the information portion by using theerror-correcting words PO and PI.

Such Reed-Solomon error-correcting product code block has a higher dataprocessing efficiency with a decrease in a ratio of a redundant portion(Pi.times.M+Po.times.N+Po.times.Pi) of the error-correcting word withrespect to the whole word referred to as redundancy ratio, namely(M+Po).times.(N+Pi). On the other hand, the error-correcting capabilityis also heightened with respect to the random error and the burst errorwith an increase in the Pi and Po.

Here, it is known that the Reed-Solomon error-correcting code blockhaving small M and N, namely small Pi and Po has a lower correctingcapability because of relatively higher probability of error in errorcorrection in the case where the Reed-Solomon error-correcting productcode blocks having the same redundancy ratio are compared with eachother.

On the contrary, it is known that since Pi and Po can be increased atthe same redundancy ratio with an increase in M and N, a higherror-correcting capability can be obtained. However, such capabilitycannot be realized unless the constraint conditions described below aresatisfied.

A first constraint condition is that M+Po and M+Pi must be equal to orless than 255 bytes as a code length for constructing the Reed-Solomonerror-correcting product code block (in the case where the length of thecode is eight bits). Incidentally, Pi described above refers to the PIseries error-correcting code length while Po refers to the PO serieserror-correcting code length.

A second constraint condition is a cost constraint resulting from thescale of the hardware.

By the way, when considered on the basis of the above conditions,optical disk standards such as a DVD-ROM, a DVD-RAM, a DVD-R or the likewhich are the information recording media in recent years are madepublic as a standard in which the improved Reed-Solomon error-correctingproduct code block is adopted. Out of these standards, the DVD-ROM andthe DVD-RAM are established as DIS16448 (DVD-ROM having a diameter of 80mm) and DIS16449 (DVD-ROM having a diameter of 120 mm) and DIS16825(DVD-RAM).

In this DVD standard, the above idea is adopted with respect to theerror-correcting word processing method so that the error-correctingcapability is remarkably improved with error-correcting word having asmall redundancy ratio as compared with the method used in theconventional optical disks.

The concept on the error-correcting method of the DVD is basicallydescribed above, the fundamental problem is to what level the target ofthe random error-correcting capability and the burst error-correctingcapability is to be set. In order to set such level, the recordingmethod of the recording medium and the generation of defects resultingfrom the handling thereof must be considered.

The recording/reproducing method is determined from therecording/reproducing beam spot size resulting from the recordingwavelength and the optical system characteristic in the optical disksystem. Here, the recording density constitutes a large factor in thedetermination of the error-correcting method. In particular, in thedetermination of the burst error correction capability, the defectlength such as scratches or the like generated in the handling of thediscs can be determined from experience. With respect to theerror-correcting capability, the multiplication of line recordingdensity by the physical defect length constitutes a burst error lengthof information data with the result that the error correcting capabilityis required to be raised in the improvement of the recording density.

The recording density can be described as follows with particularreference to the reproduction system.

When, a light source wavelength is denoted by .lambda., and a numericaperture of an object lens is denoted by NA, the recording densitystands proportional to (NA/.lambda.).sup.2. The wavelength adopted inthe DVD is 650 nm while NA is 0.6.

In the error-correcting method, a row side inner parity of RS (182, 172,11) and a column side outer parity of RS (208, 192, 17) are adopted bymeans of PI (inner parity)=10 bytes and PO (outer parity)=16respectively with respect to the (M.times.N)=(192.times.172) bytesinformation data block in terms of the Reed-Solomon error-correctingproduct code (RS is referred to as Reed-Solomon). The block used in thiserror-correcting method is referred to as the error-correcting productcode block.

Here, with respect to the error-correcting product code block, the erroris corrected in the PI series at first, and an error mark is attached toa row whose error cannot be corrected. Thereafter, at the time of theerror correction on the PO series, the error mark is treated as an errorposition. When the so-called “erasure correction” method for calculatingand extracting only error patterns is used, a maximum of 16 rows ofburst errors can be corrected. In the DVD, since the recording densityis data bit length=0.267.mu.m, 0.000267.times.8.times.182.times.-16=6.2mm is given. It is possible to say that about 6 mm bursterror-correcting capability is given.

However, as a next generation DVD an examination is started on anoptical disk having a large capacity resulting from further increase inthe density. For the increase in capacity exceeding the DVD, therecording density must be increased. Recently, in order to meet suchrequest, a blue laser diode having a wavelength of 450 nm is madepublic. When such laser diode is used, it is expected that the recordingdensity can be improved by about 2.6 times in the optical system similarto the DVD or the like. With the improvement in the optical system, fourto five times higher density can be realized so that a fine image suchas a high definition image such as a Hi-Vision or the like can berecorded for two or more hours on one disc.

In such increase in the density (for example, the line density is abouttwice as compared with the conventional one), only about 3 mmerror-correcting capability can be provided with respect to the bursterror when the conventional error-correcting method is introduced.

Furthermore, as described above, the error-correcting word length is 255bytes at most as long as 1 word=8 bit system processing system is used.Since the PO series is 208 bytes in the DVD standard, the burst errorcorrecting capability is close to the limit in the aboveerror-correcting method so that only little improvement can be expected.

In order to expand the error-correcting word length, the word length mayonly be lengthened. With respect to the word length, a multiple of eightcan be easily used. As a consequence, 1 word=16 bits can be considered.The scale of the error-correcting circuit as hardware is extremely largeas compared with the conventional one so that there arises manyproblems.

In such a case, there is generally available a technique in which theburst error-correcting capability is improved while maintaining theerror-correcting code length by adopting a data interleave to scatterthe burst error.

However, the data interleave is not adopted even in the DVD standard.The reason goes as follows: in the case where an error is created whichexceeds the error-correcting capability in the reproduction processingin the case of an image signal in which information data is compressed,the error data is scattered with the result that a disadvantage of thereproduced image is generated at many positions. In the reproductionprocessing of the image signal, it is thought that processing ofconcentrating and reproducing disadvantageous images as much as possibleis favorable as a processing of generated disadvantage. This is becausethe processing can be completed with the reproduction of an instantdisadvantageous image.

Besides, a structure close to the current DVD system is favorable forthe upper compatibility with respect to the next generation system.

Points Noted by the Inventors of the Present Invention

Generally, in the error-correcting processing method such as a packagemedium or the like, the Reed-Solomon product code block method isintroduced in many cases. This is because high performance and highefficiency can be expected with this method in the case where defecterror data such as defects generated in package medium or the like isdetected and corrected.

With respect to the unit of processed data, 1 word=1 byte (8 bits) isfavorable. When the application development of the system is considered,it is required to suppress a processing circuit to an appropriatehardware scale. Besides, this fact is required for facilitating aconnection to the recording medium and the transmission channel becausea front and rear processing circuit is provided in the recording on therecording medium and data transmission to the transmission channel inaddition to the error-correcting processing.

Under these circumstances, use of the Reed-Solomon error-correctingproduct code block used in the current DVD is optimal as anerror-correcting method which can corresponds to a large improvement inthe recording density of the recording medium under the abovesurrounding situation.

row side inner parity RS (182, 172, 11)

column side outer parity RS (208, 192 17)

Here, the problem is that it is required to settle the improvement ofthe burst error correcting capability.

In order to heighten the burst error correcting capability, the errormay only be scattered in the error detecting and correcting capabilityin each of the correction code. However, an image and an acoustic signalas information data are subject to compression coding. In a system forrecording and reproducing the compression signal, a data structure orerror-correcting processing system is desirable which is capable ofsuppressing information breakdown to a minimal level in the finalreproduction of the image and acoustic signal.

In particular, as countermeasures for dealing with the burst error, thenumber of errors in one error correction block is decreased byscattering the error signal, so that the error-correcting capability canbe improved. However, in the case where errors are present in the numberexceeding the error-correcting capability, the dispersion of the errorsignal will result in the expansion of the damage done on the wholedata. Consequently, it is difficult to adopt the method using the errordata dispersion, namely, the data interleave, which constitutes thebasic concept of heightening the burst error-correcting capability.

BRIEF SUMMARY OF THE INVENTION

(1) Therefore, an object of the present invention is to provide a dataprocessing method and apparatus and a reproducing method and apparatus,wherein the creation of an outer parity is devised which directlyaffects a burst error-correcting capability.

(2) Furthermore, an object of the present invention is to provide a dataprocessing method and apparatus and a reproducing method and apparatuswhich can largely improve a burst error-correcting capability even in acorrection flag redundancy ratio which is the same as the conventionalone in an error-correcting method based on byte data.

(3) Furthermore, an object of the present invention is to provide a dataprocessing method and apparatus and a reproducing method and apparatuswhich are capable of realizing an error-correcting process on ahigh-density optical disk using a blue laser having a short wavelengthup to a physical error-correcting length larger than the conventionalone.

(1A)

That is, in the first method of the present invention, one matrix blockis such that a plurality of M rows.times.N columns data sectors areaggregated and formed. Furthermore, sub-blocks each having the samenumber of Y rows is such that one matrix block is divided and formed.Furthermore, Y error-correcting word blocks P0-1 through P0-y arecreated with respect to the data in the row (vertical) direction of Ysub-blocks. Then, one error-correcting code block (ECC block) is suchthat Y error-correcting word PO-1 through P0-y are scattered andarranged in bytes at the end of each row. Furthermore, at the end ofeach row, a configuration is formed such that an error-correcting wordPI in the column (horizontal) direction is added at the end of eachblock.

Then, the present invention provides either a data processing method orapparatus characterized by constructing the ECC block, or the presentinvention provides a recording medium in which such ECC block isrecorded. Furthermore, the present invention provides a method and anapparatus for reproducing the matrix block by processing such ECC block.

Specifically, for example, in the beginning, a main block is constructedwhich has larger than the maximum byte numbers(=255 bytes) and has twiceas many as rows, the block being constructed as a code length in theReed-Solomon code in which 8 bits=1 bytes are set as data unit.

Then, for example, an even-number row and an odd-number row of the mainblock are separated to construct two sub-blocks. An outer parity iscreated for each row separately in each block. The inner parity iscreated in each of the rows like the prior art.

(2A)

Furthermore, in another method of the present invention, oneerror-correcting code block (ECC block) is such that Y error-correctingword blocks PO-1 to PO-y are scattered and arranged in bytes at the endrow of the data sector. Furthermore, this error-correcting code blockhas a configuration such that an error-correcting word PI in the column(horizontal) direction is added at the end of each row.

Then, the present invention provides either a data recording method orapparatus characterized by constructing the ECC block, or a recordingmedium on which such ECC is recorded. Furthermore, the inventionprovides a method and apparatus for reproducing the matrix block byprocessing such ECC block.

Specifically, for example, in the beginning, a main block is constructedwhich has larger than the maximum byte numbers (=255 bytes) and hastwice as many as rows, the block being constructed as a code length inthe Reed-Solomon code in which 8 bits=1 byte are set as data unit. Then,for example, in a first sub-block comprising an even-row of the formerhalf area of the main block and an odd-row of the latter half area ofthe main block, and a second sub-block comprising an odd-row of theformer half area of the main block and an even-row of the latter halfarea of the main block an outer parity is separately created for each ofthe rows. Furthermore, an inner parity of each of the first and thesecond sub-block is created in each of the rows in the conventionalmanner.

When a varied error-correcting code block as described above is adopted,the error data is constructed in a scattered manner as seen from theerror-correcting system of the outer parity. There is realized astructure in which actual recording and transmission data observes theactual data order so that no error dispersion is generated at thedecoding time.

That is, in the error-correcting method using the conventionalerror-correcting code block, an outer parity and an inner parity arecreated and odd to A rows.times.B columns data block. However, in thepresent invention, as the number of rows of the data block, the numberof rows is adopted which is larger than the number of rows of themaximum code length which can be subjected to error coding. Theerror-correcting code series (PO series) in the row (vertical) directionis divided into two sets. As a consequence, it becomes possible to dealwith a data block larger than the conventional one as anerror-correcting code block. Furthermore, it also becomes possible tonot to scatter the data transmission order which is important in dealingwith a compressed image signal or the like so that a bursterror-correcting capability can be largely improved.

As described above, in the error-correcting word comprising a productcode in which, for example, 8 bits=1 byte constitutes a data unit, it isrequired that the number of rows and the number of columns are selectedso that the byte number of the block in which the information data andthe error-correcting word are odd becomes 255 bytes.times.255 bytes.

However, generally the information data basically takes a sectorstructure in which the data amount obtained by adding an ID(Identification Data) and a certain amount of control signal are odd tothe data having 512 bytes, 1024 bytes, 2048 bytes, 4096 bytes or thelike. Thus, a plurality of sets of such sectors constitute anerror-correcting block. Furthermore, numeric values such as 8, 16, and32 suitable for binary processing is favorable as the number of sectorsin the error-correcting blocks for taking a good timing with othersignal processing. When such condition is added, the number of rows andthe number of columns are limited so that the number of rows and thenumber of columns become about 200. As one of such example, in thestructure in which the conventional DVD standard is adopted, 172bytes.times.12 bytes configures one data sector, and 16 sectors areclustered to configure a data block.

Here, 16 bytes outer parity is generated with respect to the data ofeach column (12.times.16=192 bytes) to scatter and add the outer parityto each row (16) by one byte. As a consequence, 16 sector data block isconfigured which is a set of (12+1) rows.times.172 bytes block (onesector).

Here, furthermore, 10 bytes inner parity is created with respect to(12+1) rows.times.(172+10) rows error-correcting block. 172.times.12bytes one data sector is such that ID, 12 bytes control signal and 4bytes error sensing code EDC are inserted into the 2048 bytes main data.Consequently, a product code block can be realized which has a verysmall redundancy ratio and which enable very efficient detection anderror.

However, increasing the number of rows in the row (vertical) directionis limited as it is, and it is impossible to improve theerror-correcting capability with burst characteristic without raisingthe redundancy ratio.

Then, according to the present invention, the error-correcting block inthe DVD standard is set to two blocks unit. The even-number row and theodd-number row are separated and handled to create an error-creatingword PO in each row direction of the even-number row and the odd-numberrow. As a consequence, the burst error-correcting capability can beimproved by two times. The error-correcting block is set to 32 blocksunit. However, the method of the present invention can be used bysomewhat correcting the data reading order of the conventional DVDerror-correcting method. Furthermore, there is an advantage in that thedata processing in the conventional sector unit can be used so that themethod can bee linked to the application standard used in the DVD as itis.

The present invention can be described in the following manner in termsof the constituent element.

(1B)

According one embodiment of the present invention, there is provided adata processing method characterized in that:

digital data is processed in bytes to constitute one information datablock in (M.times.N) bytes of M rows.times.N columns;

data is arranged in bytes in the information data block, so that data isarranged in the data transmission order from the 0th column to the(N−1)-th column for each row while data is arranged in the datatransmission order from the 0th row to the (M−1)-th row;

(K.times.M) rows.times.N columns matrix block is further arranged whichis a set of the information data block, and which is constituted of Kinformation data blocks composed of information data blocks from the0-th information data block to the (K-1)-th information data block whichcontinue in the data transmission order;

on each column of (K.times.M) bytes of the matrix block, anerror-correcting word PO-a (K.times.Q) or PO-a ((K/2).times.Q) bytes iscreated at least with respect to only even-number data (K.times.M/2)bytes, and an error-correcting word PO-b (K.times.Q) or PO-b((K/2.times.Q) bytes is created at least with respect to only odd-numberdata (K.times.M/2) bytes;

PO-a and PO-b are scattered and arranged into K information data blockswhich is constituted of (M.times.N) bytes of M rows.times.N columns;

each column of N columns is formed as (K.times.(M+Q)) or(K.times.(M+2Q)) bytes of Reed-Solomon code PO (Q is an integer of 1 ormore); and

the error-correcting word P bytes is further added for each row of Nbytes and each row of (K.times.(M+Q)) or (K (M+2Q)) rows is formed as(N+P) bytes Reed-Solomon code PI;

whereby as an overall blocks an error-correcting product code block isrealized which constitutes (K.times.(M+Q)).times.(N+P)) or(K.times.(M+2Q)).times.(N+P)) bytes Reed-Solomon error-correcting wordhaving K information data block of (K.times.M.times.N) bytes asinformation portion.

According to the present invention, an error-correcting code block isconstituted wherein the sum of one information data block of (M.times.N)bytes and an average word bytes added to the data block becomes adefinite value (M+Q).times.(N+P) or (M+2Q).times.(N+P).

(2B)

According one embodiment of the present invention, there is provided adata processing method comprising:

digital data is processed in bytes to constitute one information datablock in (M.times.N) bytes of M rows and N columns;

data is arranged in bytes in the information data block, so that data isarranged in the data transmission order from the 0th column to the(N−1)th column for each row while data is arranged in the datatransmission order from the 0th row to the (M−1)th row;

(K.times.M) rows.times.N columns matrix block is further constructedwhich is a set of the information data block, and which is constitutedof K information data blocks-composed of information data blocks fromthe 0th information data block to the (K−1)th information data blockwhich continue in the data transmission order;

on each row of (K.times.M) bytes of the matrix block, anerror-correcting word PO-a{(K/2).times.Q bytes} is created with respectto the (k/2).times.(mi+mj) bytes which is constituted by aggregating theeven-number rows and the odd-number rows specified in the K informationdata block order, and an error-correcting word PO-b {(K/2).times.Qbytes} is created with respect to the (K/2).times.(mj+mi) bytes which isconstituted by aggregating the remaining even-number rows and theodd-number rows specified in the K information data blocks;

the PO-a and the PO-b are scattered and arranged into the K informationdata blocks composed of (M.times.N) bytes of M rows.times.N columns;

each column of N columns is formed as two sets of Reed-Solomon code POof (K/2).times.(mi+mj)+Q) bytes and (K/2).times.(mj+mi)+Q) bytes(however, M=mi (the number of even-number rows)+mj (the number ofodd-number rows) and (Q is an integar of 1 or more); and

the error-correcting word of P bytes is further added for each row of Nbytes;

whereby as an overall block an error-correcting product code block isrealized which constitutes (K.times.(M+Q).times.(N+P)) or(K.times.(M+2Q)).times.(N+P)) bytes Reed-Solomon error-correcting wordhaving K information data block of (K.times.M.times.N) bytes asinformation portion.

As a consequence, two sets of Reed-Solomon codes P on each row in thecolumn direction constitute an error-correcting product code in whichrows constituting respective code series are alternately arranged.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a view showing a (M.times.N) bytes of information block.

FIG. 2 is a view showing a structure of (K.times.(M.times.N)) when kpieces of the (M.times.N) bytes information blocks are aggregated.

FIG. 3 is a view showing a structure of a correction block in which theerror-correcting code is added to the (K.times.(M.times.N)) code in theproduct code structure.

FIG. 4 is a structure of the correction block in which theerror-correcting word PO (K.times.Q) is added to each of the informationdata block in Q bytes so that the information block added with acorrection flag has the same structure.

FIG. 5 is a view showing a structure of information data block addedwith the error-correcting code of FIG. 4.

FIG. 6 is a view in which a structure of the information data block ofFIG. 5 is shown in the code length used in the DVD standard.

FIG. 7 is a view showing one example of a structure of theerror-correcting block according to the present invention.

FIG. 8 is a view showing a state in which an error-correcting word PO isscattered and arranged on the (M.times.N) bytes information data block.

FIG. 9 is a view shown for explaining one example of theerror-correcting word PI series according to the present invention.

FIG. 10 is a view shown for explaining another example of theerror-correcting word PI series according to the present invention.

FIG. 11 is a view shown for explaining another example of theerror-correcting word PO series according to the present invention.

FIG. 12 is a view showing another example of a process at the time ofcreating an error-correcting block is created according to the presentinvention.

FIG. 13 is a view showing a state in which the error-correcting word isscattered and arranged on each of the information data block accordingto the present invention.

FIGS. 14A and 14B are views showing an example in which error-correctingwords P0-a and PO-b are arranged on (M.times.N) bytes of informationdata block according to the present invention respectively.

FIG. 15 is an explanatory view showing a sector link portion, the viewbeing shown for explaining a problem at the time when anerror-correcting block is structured with the method shown in FIG. 12.

FIG. 16 is a view showing one example of a process at the time ofcreating the error-correcting block according to the present inventionin the case where the error-correcting capability is further raised.

FIG. 17 is an explanatory view showing a block in the midst of thecreation of the error-correcting block in which the error-correctingcapability is improved.

FIG. 18 is a view showing a state in which the error-correcting word POis scattered and arranged on each information data block of theerror-correcting block in which the error-correcting capabilityaccording to the present invention is improved.

FIG. 19 is an explanatory view showing a sector link portion at the timewhen the error-correcting block is structured in a method shown in FIGS.16 and 17.

FIG. 20 is a view for explaining a sector link portion at the time whenthe error-correcting block is structured in a method shown in FIGS. 16and 17 and an advantage of the present invention.

FIG. 21 is a view for explaining a sector link portion of theerror-correcting block created in another embodiment of the presentinvention.

FIG. 22 is a view for explaining a sector link portion of theerror-correcting block created in still another embodiment of thepresent invention.

FIG. 23 is an explanatory view showing a process of creating an ECCblock and a recording medium according to the present invention.

FIG. 24 is an explanatory view showing a structure of a data sector inthe DVD.

FIG. 25 is an explanatory view showing a state in which the sectoraccording to the present invention is blocked into ECC blocks.

FIG. 26 is an explanatory view showing a state in which the ECC block isdivided into to two divided blocks which observes the rule of thepresent invention so that a PO series error-correcting word is added toeach of the divided blocks.

FIG. 27 is a view showing a state in which the two divided blocks whichobserves the rule of the present invention shown in FIG. 15 areintegrated so that PI series error-correcting word is added to the twodivided blocks.

FIG. 28 is an explanatory view showing a state in which the PO seriescode is interleaved in the ECC block.

FIG. 29 is a view showing a reproduction processing apparatus of the ECCblock according to the present invention.

FIG. 30 is a view showing another embodiment of a method for creating aPI series error-correcting word of ECC block according to the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, referring to the accompanying drawings, embodiments of thepresent invention will be explained.

In a structure of an error-correcting information data block in which anerror-correcting code is created and added to the information datablock, the Reed-Solomon error correction is used many times forheightening the random error and burst error correction capability.Furthermore, generally, in the digital data processing, a unit of 8 bitsconstitutes one byte. In consideration of other aspects of thedevelopment, such concept is favorable in the data processingefficiency.

Hereinafter, a detailed explanation will be given by referring to thedrawings and the DVD standard.

FIG. 1 is an M row.times.N columns information data block. In the fieldof computers, 128.times.(multiple of 2) is used as processed informationdata block.

In the DVD standard, 2048 bytes are used an information block unit. Byadding ID and a control code or the like to 2048 bytes main data, 2064bytes is set to constitute 12 rows.times.172 columns information datablock. When an attempt is made to gain an expected error-correctingcapability by directly adding an error-correcting code to(M.times.N=12.times.172) byte block, the redundancy ratio of thecorrection code becomes too high. Then, (K.times.(M.times.N)) bytesinformation data block is constructed by aggregating K information datablocks.

FIG. 2 is a view showing this (K.times.(M.times.N)) bytes informationdata block. In the DVD standard, K=16 is adopted.

The row (vertical) direction in the information data block is the(K.times.M) bytes data. In the (K.times.M) byte data in each of the Nrows, (K.times.Q) bytes error-correcting code is created and added.Next, the row (vertical) direction in the information data block of FIG.2 is N bytes data. Furthermore, the row number is(K.times.M)+(K.times.Q) row because of an increase in the previouserror-correcting code (K.times.Q). In each of the(K.times.M)+(K.times.Q) row, P bytes which are error-correcting code iscreated and odd.

FIG. 3 is a view showing a state in which (K.times.Q) byteserror-correcting code and P bytes error-correcting code are added to(K.times.(M.times.N)) information data blocks.

In the DVD standard, Q=1 and P=10 are given.

Next, (K.times.Q) bytes error-correcting code is scattered by Q bytesand is odd to K (M.times.N) bytes information data blocks respectivelyso that each of the information data blocks assumes the sameconfiguration.

The processing is significant in that all the K information data blocksare formed in the same structure. That is, (N.times.M) bytes informationdata is odd with ID showing an address of the information data. However,since the error-correcting code (K.times.Q.times.172) which is an outerparity PO is all error-correcting code, the ID cannot be added thereto.Then, this error-correcting code is scattered and arranged in each ofthe information data block so that all the information data blocksassume the same structure and have the ID.

Incidentally, the order of scattering and arrangement is such that(K.times.Q) row is scattered and arranged in each information data blockafter creating the error-correcting code in the row (vertical)direction. Otherwise, after an error-correcting code in the row(horizontal) direction is created and added to each row, theerror-correcting code in the column (horizontal) direction is createdand added to each row, the error-correcting codes of (K.times.Q) rows inthe row (vertical) direction are scattered and arranged on eachinformation data block. In any order, the method of the DVD standardyields the same result.

FIG. 4 is a view showing a new block structure in which (K.times.Q) rowsof the error-correcting words are scattered and arranged in each of Kinformation data blocks by Q. In the DVD standard,(K.times.(M+1).times.(N+P)), namely, [16.times.(208.times.182)] byteserror word block is constructed.

FIG. 5 is a view showing a structure of one information data block(M+Q).times.(N+P) to which the error-correcting code is added. On thefront row, an ID and a control signal (CNT-sig) which constitute addressinformation of the information data block is arranged while theerror-correcting word Q in the row (vertical) direction is arranged atthe end row. In the DVD standard, Q=1 is set, and in this structure, thenumber of K can be increased until K.times.(M+Q) becomes 255.

FIG. 6 is a view showing in detail the information data block of FIG. 5.At the last of the main data, the EDC is added.

FIG. 7 is a view showing one embodiment of the information data blockaccording to the present invention.

N columns.times.M rows of K information data blocks as shown in FIG. 1are aggregated so that (K.times.M) rows.times.N columns matrix blocksshown in FIG. 2 are constructed. Here, (K.times.Q) bytes or(K/2.times.Q) bytes error-correcting code (error-correcting word) PO-ais created with respect to (K.times.M/2) bytes data on each column ofthe even-number row.

Next, (K.times.Q) bytes or (K/2.times.Q) bytes error-correcting code(error-correcting word) PO-a is created with respect to (K.times.M/2)bytes data on each column of the odd-number row.

PO-a and PO-b created here are scattered and located on each of(M.times.N) bytes of K information data blocks are scattered andarranged.

Here, in the case of PO-a=PO-b=(K.times.Q), PO-a and PO-b arerespectively scattered and arranged by Q on each of the (M.times.N)bytes information data blocks while in the case ofPO-a=PO-b=((K/2).times.Q), PO-a is scattered and arranged on theeven-number-th information data blocks or the former half of theinformation data block out of K information data blocks and PO-b arescattered and arranged on the odd-number-th information data blocks orthe latter half of the information data blocks.

Here, in the case where M=12 and N=172 are set in the same manner as theDVD standard of FIG. 1 according to the present invention, setting K=32(16.times.2), Q=1 and PO-a=PO-b=16 leads to the creation of theerror-correcting word PO-a for the even number and the error-correctingword PO-b for the odd number with respect to the 172columns.times.(12.times.32)=384 rows of the error-correcting data block.Then, on the even number-th of each of 32 information data blocks, PO-ais scattered and arranged. On the odd number-th thereof, PO-b isscattered and arranged, so that 32 information data blocks of (12+1)bytes.times.172 bytes are formed. Furthermore, 10 bytes error-correctingword PI is added so that 32 information data blocks of (12+1)rows.times.(172+10) columns are formed. This is the error-correctingproduct code block.

Each of the information data blocks after the addition of theerror-correcting word has the same structure as the conventional blockshown in FIG. 6. However, the value of K is different. The informationdata block of DVD are constituted of main data 2048 bytes composed of 12rows and 172 columns, an ID and a control signal (12 bytes), and an EDC(4 bytes). On the whole, 2064 bytes information data block constitutes aunit.

The present invention is not restricted to the above embodiment.

As another embodiment, an information data block is considered whereinthe ID, the control signal (24 bytes) and the EDC (8 bytes) are added to(M=24 rows).times.(N=172 columns)=4096 bytes main data (informationblock). Now when PO-a=PO-b=16 bytes is established at K=16 and Q=1, onebyte is scattered and arranged to each of the information data blocksfrom PO-a and PO-b respectively. One information data block after addingthe error-correcting word in this case assumes a structure shown in FIG.8.

Next, the error-correcting code PI will be explained.

FIG. 9 is a view showing a formation series of the error-correcting word(inner parity) which is one example of the present invention. The innerparity Pi is created with respect to the data in the column (horizontal)direction which is a data transmission order.

FIG. 10 is a view showing a variation for forming an error-correctingword (inner parity) which is another embodiment of the presentinvention.

With respect to M rows.times.N columns data of the information datablock, the formation of the (N+P) bytes Reed-Solomon code (inner parity)PI is realized in data from 0-th column to the ((N+P)−1)-th column and0-th row to the (M-1)-th row. In the creation of the PI serieserror-correcting code with respect to the information data block towhich PO is added, each row and each column are increased on the basisof the byte data of each front column to rotate and arrange the rownumber (M) obtained as a result of increase to move to the 0th row whenthe increase result of the row becomes (M)-th row thereby constituting(M) sets of PI series error code.

In the conventional recording density, one to two bytes error isscattered as a random error. However, in a high-density recording, theerror is increased up to five bytes.

Then, the recording arrangement is not changed with respect to the dataorder by setting the error-correcting series to a data set series havinga jump arrangement different from the recording order. However, sincethe error-correcting code series is different from the recording order,a small concentration error is scattered in the error-correctingprocessing so that the random error capability in the execution can beimproved.

FIG. 11 is a view showing a method for forming a PO serieserror-correcting code according to another embodiment of the presentinvention.

In FIG. 11, (K.times.M) rows.times.N columns error-correcting data block(matrix block) like the conventional DVD standard is formed in arecording order. The block B2 is a current block while the block B1 is ablock before the block B2. In the creation of the PO serieserror-correcting data block Po, an even-number data of the currenterror-correcting data block is aggregated in a set to constitute a datablock B22. Next, when the error-correcting code Po is created, the codeis scattered and arranged in the current error-correcting data block B22to constitute the block B23. Thereafter, to this block B23, the PIseries error-correcting code Pi is created to add each row.

In this error-correcting word data processing method, PO series issubjected to an overlapping processing. However, this method has anadvantage in that the required reading data scope can be small in anarbitrary two information data blocks.

Furthermore, the present invention is not limited thereto.

FIG. 12 is a view showing a process of creating the ECC block shown forexplaining a basic concept of the present invention.

An object of the present invention is to improve the error-correctingcapability in the case where the burst error is generated. For thispurpose, the error-correcting processing block by the outer parity isscattered.

In explanations of FIGS. 1 and 2, the information data blocks(N.times.K) bytes are clustered into K (here K=16) sets. Then, an outerparity and an inner parity is added to the set data blocks to generatethe ECC blocks. However, in this invention, two sets of information datablocks are used to generate the ECC block. Consequently, the number K ofthe information data blocks to be handled is 32 in the presentinvention.

FIG. 12 is a view showing a state in which two sets of information datablocks (A-10 and A11) are prepared. Next, the even-number data blocksand the odd-number data blocks (A-10 and A-11) are divided into twoblocks respectively. Both the even-number blocks and the odd-numberblocks are given in two blocks respectively. Hereinafter, the two blocksare referred to as even-number blocks (B-10), (B-11). With respect tothe even-number block and the odd-number block, an outer parity iscreated and added. Hereinafter, the outer parity added to theeven-number block (B-10) is denoted by PO-a while the outer parity addedto the odd-number block (B-11) is denoted by PO-b. The outer paritiesPO-a and PO-b are referred to an error-correcting code orerror-correcting word.

Here, as the byte numbers of the outer parity PO-a, (K.times.Q) bytes or(K/2.times.Q) bytes are given with respect to the (K.times.M/2) on eachcolumn. As the byte numbers of the outer parity PO-b, (K.times.Q) bytesor (K/2.times.Q) bytes are given with respect to the (K.times.M/2) oneach column.

Next, the separated even-number row and the odd-number row are broughtback to the original state. The state is shown as block C. This meansthat 32 information data blocks (M rows.times.N columns) are aggregatedas sets. Furthermore, as the outer parity, PO-a and PO-b are added.Furthermore, an inner parity PI (10 bytes) is also created and added.Next, the PO-a and PO-b created here are scattered and arranged intoK(=32) information data blocks each having (M.times.N) bytes.

FIG. 13 is a view showing a state in which each outer parity PO isscattered and arranged into each information data blocks. Here, in thecase of PO-a=P-b=(K.times.Q), information data blocks are scattered andarranged by Q bytes to each of (M.times.N) bytes information data blocksfrom PO-a and PO-b respectively. In the case ofPO-a=Po-b=((K/2).times.Q)-, PO-a is scattered and arranged intoeven-number information blocks, or the former half information datablocks while PO-b is scattered and arranged into the odd-numberinformation data block, or the latter half information data blocks.

FIG. 14A is a view showing the state in which one information data blockafter the dispersion and arrangement of the PO in the case ofPO-a=PO-b=(K.times.Q). Furthermore, FIG. 14B is a view showing the statein which one information data block is taken out after the dispersionand arrangement of PO in the case of PO-a=PO-b=((K/2).times.Q).

The ECC blocks shown in FIG. 13 are recorded on a recording medium fromthe front recording sector in order. Furthermore, in the transmissionsystem, the blocks are recorded from the front recording sector inorder. On the reproducing side or the receiving side, the ECC blocks areincorporated into a buffer memory from the front thereof in order. Inthe case where the ECC blocks having a unit shown in FIG. 13 is restoredto a form as shown in the even-number block B-10 shown in FIG. 12, theodd-number block B-11 in an error-correcting processing so that POsystem error-correcting processing is carried out. As a consequence,even when a burst error is present at the step of ECC block, the erroris scattered to the even-number block and the odd-number block, so thatthe error-correcting capability is raised.

Here, in the present invention, the following points are noted tofurther raise the error-correcting capability.

FIG. 15 is A view shown for explaining noted point of the presentinvention.

In the above embodiment, the even-number row and the odd-number row oftwo set information data blocks are simply separated to create the POseries code (PO-a and PO-b) corresponding to the even-number block andthe odd-number block. Next, the even-number block and the odd-numberblock are brought back to the arrangement (the state in which theeven-number row and the odd-number row are alternately arranged), sothat the PO series code as shown in FIG. 14A or FIG. 14B are scatteredand arranged. This creates the ECC block as shown in FIG. 13.

Here, the PO series code is arranged by Q bytes between sectors. Here, alinkage between the sector (the even-number sector) and the sector (theodd-number sector) is noted (in this example, the sector includes 12rows of information data block). Then, on the final row of the firstsector, a part of PO-a created by using the even-number block (Q bytes(N+P)) is located and the front row of the second sector becomes aneven-number row. Consequently, the front row of the second sector (theeven-number row) is present in the even-number row.

As a consequence, as seen from the PO series, the PO series data isconsecutively arranged for two row portions. An aim of the presentinvention is to create an arrangement of each row as a repetition ofodd-numbers and even-numbers while the error-correcting word is createdcorresponding to the odd-numbers and the even-numbers respectively. As aconsequence, when the errors are corrected, the even-number rows and theodd-number blocks are separated thereby enabling error correctionprocessing in respective blocks. Consequently, the present invention isintended to scatter the error even at the time of the generation of theburst error to the ECC block to improve the error-correcting capability.

However, as has been explained in FIG. 15, when the same PO series datais arranged consecutively for two rows portion, the expected result ofthe error dispersion cannot be obtained at the time of the generation ofthe burst error at this portion.

Therefore, in the present invention which has been further improved, theprevious even-number block and the odd-number block are not obtained, sothat the following PO-a creation blocks and the PO-b creation blocks areobtained. That is, by referring to FIG. 16, the two blocks will beexplained.

As shown in FIG. 16, using the two set information data block (A-10,A-11) which constitutes the data transmission order is the same as theprevious example.

Here, in the PO-a creation block (E-10), the even-number row in theeven-number sector and the odd-number row in the odd-number sector areaggregated and created from the two set information data blocks (A-10and A-11). And in the PO-b creation block (E-11), the odd-number row inthe even-number sector and the even-number row in the odd-number sectorare aggregated and created from the two set information data blocks(A-10 and A-11).

FIG. 17 is a view showing the state in which the even-number row and theodd-number row of the above separated PO-a creation block (E-10) andPO-b creation block (E-11) are brought back to the original state andthe even-number block and the odd-number block are linked in order. Thisblock F is a set in which 32 information data blocks (N columns.times.Nrows) are aggregated. Furthermore, as the outer parity, PO-a and PO-bare added thereto. Furthermore, the inner parity PI (10 bytes) is alsoadded thereto. Next, the PO-a and PO-b created here is scattered andarranged in K(=32) (M.times.N) bytes information data blocks toinformation data blocks each having (M.times.N) bytes. As a consequence,between respective sectors, PO series code is arranged Q bytes.

FIG. 18 is a view showing the ECC block at this time. A method forscattering and arranging the PO series is explained in FIGS. 13, 14A and14B.

FIG. 19 is a view in which a linkage between the sector (the even-numbersector) and the sector (the odd-number sector) are noted in the ECCblock. (In this example, the sector includes the 12 line informationdata blocks.) Then, at the last row of the first sector, a part (Qbytes.times.(N+P)) of the PO-a created by using the block E-10 islocated at the last row of the first sector. The front row of the secondsector is the even-number row, but the front row of the second sector isthe PO-b series as explained in FIG. 16. As a consequence, the row atthe linkage between the odd-number sector and the even-number sector issuch that the row at the PO-a series and the row at the Po-b series arealternately arranged.

Consequently, the row at the PO-a series and the row at the Po-b seriesintended by the present invention are alternately arranged to form theECC block with the result that an object of improving theerror-correcting capability with respect to the burst error iseffectively attained. That is, a burst error-correcting capabilityhaving a twice longer code length than the conventional method isprovided by using the ECC blocks which are constituted in this manner.

In the above embodiment, there is shown a case in which the number ofrows of one sector is M=12 (even number). Here, there is considered acase in which M is an odd number (for example, 11).

Now, in the same manner as the above embodiment, suppose that PO-acreation block (E-10), PO-b creation block (E-11) are created, and PO-aand PO-b are created with respect to the respective blocks. Then, eachrow of the PO-a creation block (E-10) and the PO-b creation block (E-11)are brought back to the original position. Furthermore, the PO-a andPO-b are scattered and arranged to create the ECC block.

FIG. 20 is a view in which the linkage between the sector (even numbersector) and the sector (odd number sector) in this ECC block is noted.(In this example, the sector includes 12 rows of information datablocks). Then, at the last row of the first sector, a part (Qbytes.times.(N+P)) of the PO-a block created by using the block E-10created by using the block E-10 is located. The front row of the secondsector becomes an even number block. The front row of the second sectoris an even number block, the PO-b series row which belongs to the blockE-11 is located as explained in FIG. 16.

As a consequence, the last row of the first sector and the row beforethe last row constitute the PO-a series row. Thus, in the case where aburst error is generated in this portion, the error-correctingcapability cannot be sufficiently displayed. However, there is anexample in which the effect of the present invention can be sufficientlyobtained even when one of the sectors is an odd-number row.

FIG. 21 is a view showing an example in which a method explained in FIG.14A is adopted as a method for arranging the error-correcting code byadopting M=9 rows as a sector. In this example, on the linkage of thesector, the following row arrangement appears. In the beginning, look atthe linkage at a portion, where the odd-number sector is arranged nextto the even-number sector. The last row as the even-number sectorinformation data block is an even number, and PO-b serieserror-correcting code is added to the last row by one row.

Further, after this PO-b series error-correcting code, PO-a serieserror-correcting code is arranged by one row. Here, the front row of theodd-number sector is an even-number row. This even number is used tocreate PO-b series code as shown in the block E-11 of FIG. 16.Consequently, at the linkage portion of the even-number sector and theodd-number sector, PO-b and PO-a are alternately arranged.

Next, look at a linkage portion where the even-number sector is arrangednext to the odd-number sector. The last row as the even-number sectorinformation data block is an even number, and this row is separated intothe block E-11 shown in FIG. 16. Therefore, the last row belongs to thePO-b series. To the contrary, PO-a series error-correcting code is addedto the last row by one row. Next, after this PO-series error-correctingword, PO-b series error-correcting code is added by one row. The frontrow of the next even-number sector is an even number. The front row isseparated into the block E-10 shown in FIG. 16. Therefore, the last rowbelongs to PO-a series. As a consequence, at the linkage of theodd-number sector and the even-number sector, rows of PO-b and PO-aseries are alternately arranged.

That is, in the embodiment shown in FIG. 21, when the error-correctingwords PO-a and PO-b are arranged, the selection order is devised so thatthe row of the PO-b, PO-a, PO-b and PO-a series are alternatelyarranged.

The concept of the embodiment of FIG. 21 can be applied to the casewhere one sector is the odd-number row (for example, M=10).

FIG. 22 is an example in which one sector is an even-number (forexample, M=10), and as a method for arranging the error-correctingmethod the method explained in FIG. 14A is adopted. Furthermore, in thisexample, the block E-10 of FIG. 16 comprises an even-number row of theeven-number sector and an even-number row of the odd-number sector, andthe block E-11 comprises an odd-number row of the even-number sector andan odd-number row of the odd-number sector.

In this embodiment, the linkage at the sector assumes the following rowarrangement. The last row as the information data block of theeven-number sector is the odd-number. This row is separated with theblock E-11 of FIG. 16. Consequently, the last row belongs to the PO-bseries. In contrast, the PO-a series error-correcting code is added byone row to the last row. Next, after the PO-a series error-correctingcode, PO-b series error-correcting code is arranged by one row. Thefront row of the next odd-number sector is an even-number. In this case,the front row belongs to the PO-a series. As a consequence, at thelinkage portion of the odd-number sector and the even-number sector,rows of the PO-a, PO-b, and PO-a are alternately arranged.

FIG. 23 is a view showing a data processing procedure of a recordingapparatus to which the present invention is applied. Data for recordingis input to the data sector portion 42 from the outside to be sectored.In this embodiment, 2K bytes constitute the basic unit. An error sensingcode (EDC) is added to the data block having a 2K bytes unit data block.This data block is referred to as information data block. Thisprocessing is carried out at the EDC coding portion 43. Next, the ID foridentifying the information data block (sector) and other control signalis added to the ID adding portion 44. Next, at the scramble processingportion 45, the main information data is scramble processed.

This scramble processing is carried out for the following reasons. Thatis, in the case where the main data is an image signal or the like, “0”continuously appears in the blank portion. When such signal is handledas a recording signal, there appears a tendency that the recordingsignal becomes a repetition of the same pattern. When the same patternof the recording medium is present on the adjacent track such as anoptical disk or the like, the operation of the servo becomes unstableunder the influence of the cross talk between tracks. In order toprevent this, the scramble pattern determined by ID is used, so thatdata scramble is provided by overlapping the scramble data onto thedata.

The scrambled data (sector) is summarized in 32 sector units in thetransmission order so that the data is ECC blocked in the ECC blockportion 46. This ECC block is input to the even-number/odd-number blockportion 47. Here, the even number and the odd number are temporarilyblocked separately. Then, at the even-number and odd-number PO codingportion, each block is subjected to the PO series error-correcting wordas explained in the previous embodiment.

Next, at the PI coding portion, each row is subjected to PI serieserror-correcting coding process. Next, at the ECC blocking portion 50,the block of the even-number row and the block of the odd-number areintegrated. Furthermore, at the PO parity interleave portion 51, the POseries parity is scattered to each sector while the PO series inspectionand correcting word is interleaved to each data sector in the wholeblock.

Next, this ECC block is input to the recording sector portion 52.Furthermore, when a synchronizing signal is added with the recordingsector portion 52 and the next modulation and synchronizing additionportion 53, and is 8/16 modulated. This modulation signal is supplied toan optical pickup 55 to drive a laser diode. As a consequence, the laserlight is applied to the disc to record the signal. The disk 56 isrotated and controlled with the disk motor 57.

FIG. 24 is a view showing a structure of a data sector in the DVD formatcreated in the midst of the above recording processing. The data sectorhas 172 columns (172 bytes) and 12 rows. The first row is composed of anID (4 bytes), an IED (ID error-detecting code: 2 bytes), a CPR-MAI(copyright management information: 6 bytes), and a 160 bytes of maindata. At the end of the last row (12th row), main data and four bytes oferror-detecting code are added thereto. The remaining row are all maindata.

FIG. 25 is a view showing a state in which 32 sectors are aggregated toform an ECC block as has been described above.

FIG. 26 is a view showing the state in which the ECC block is dividedwith the rule explained in FIG. 12 or FIG. 16 to constitute aneven-number block (or PO-a creation block) and an odd-number block (orPO-b creation block) so that the PO series codes PO-a and PO-b arecreated and added with respect to respective blocks.

FIG. 27 is a view showing the state of a single ECC block in which theeven-number block (or the PO-a creation block) and the odd-number block(or the PO-b creation block) are integrated together with the code PO-aand PO-b. Furthermore, FIG. 27 shows a state in which the PO-a code arecreated and added. The arrangement order of the PO-a and the PO-b arenot limited to what is shown in the drawings.

FIG. 28 is a view showing a state in which the PO series code isscattered to each sector. This is the recording sector. To eachrecording sector, a synchronizing signal is added and further modifiedto be recorded on the recording medium.

Incidentally, according to the present invention, the PO serieserror-correcting word is created and the PI series error-correcting wordis created in the above explanation. However, this processing procedureis not limited thereto. This processing order may be the contrary. Thatis, after the data sector is ECC blocked, the PI series error-correctingcode is created so that the ECC blocks to which the PI code is added isseparated into a block in which the even-number row of the ECC blockadded with the PI code is aggregated and the block in which theodd-number row is aggregated. Thereafter, the PO series error-correctingword including the PI code may be created. Then, after that, theeven-number row and the odd-number row are re-aggregated so that, afterthat, the PO code may be distributed in the interleave processing.

FIG. 29 is a view showing an example of a structure of a reproducingapparatus to which the basic concept of the present invention isapplied.

On the disc 56, data is recorded with a recording method as previouslyexplained. A modification signal read with the pickup head 55 issupplied to the channel data reading portion 81 to provide a channel bitunit. Then at the synchronizing separation portion 82, the synchronizingsignal is separated and divided in symbol units. Next, at the decodingportion 83, the signal is decoded from 16-bit data to 8-bit data to besupplied to the sector ID detection portion 84. Here, the data isidentified and aggregated for each of the sectors to be input into theECC block creation portion 85. Here, the sectors are aggregated toprovide an EEC block unit data. The ECC block is input to the PIdecoding portion 86 to carry out the PI series error sensing andcorrecting. Next, at the PO-a decoding portion 87, the PO-a errordetection and correction is carried out so that the PO-b series errordetection and correction is carried out at the PO-b series decodingportion 88.

Next, the de-scrambling of the main data portion is conducted at thede-scramble processing portion 89. Furthermore, at the error-detectingportion 90, errors in the main data portion are detected on the basis ofthe EDC so that a normal data is taken out. This main data istransmitted to the processing portion after that via the interface.

Incidentally, at the reproduction processing, either the PI series errordetection and correction processing or the PO series error detection andcorrection processing may be carried out prior to the rest of the two.The order is not restricted to what is shown in the drawings.

By the way, in the DVD, a video object (VOB) is designated in cells, andVOB is a format in which a plurality of video object units (VOBU) areincluded. The video objects allow the inclusion of a plurality of videopackets (V_PCK), audio packets (A_PCK), and subsidiary image packets(SP_PCK). Furthermore, in the recording reproduction format, a controlpackets (RDI_PCK) including the real-time data information (RDI)arranged at the front of the VOBU. On this packet, such information asthe reproduction start-time, intermission information at the recordingtime, display control information (aspect ratio information), copycontrol information or the like. Furthermore, in this packet, areservation area is also secured.

Furthermore, the video data incorporated in the V_PCK is subjected tocompression by means of MPEG1 or MPEG2 method. Either in the MPEG 1 orMPEG 2 method, information showing an aspect ratio or the like isdescribed on a sequence head or the like. Furthermore, the GOP user datafor the line 21 can be inserted into a part of the compressed data. Thispart is used at the time of sending a character code data.

Furthermore, in the DVD standard which can be recorded and reproduced, acontrol data area is also secured for describing program chaininformation for determining the reproduction order of the programrecorded on the user data area.

Consequently, in the case where the ECC block of the present inventionis used, an area of a portion of RDI_PCK, or an arrangement portion ofthe GOP user data or a portion of the control data area are used tostore ECC block identification information showing what form the ECCblock form assumes.

When this ECC block identification information is stored, it is possibleto identify which form of the ECC block the recorded information or thetransmitted information is. As a consequence, the present invention canbe added and provided on the conventional DVD reproducing apparatus sothat the present invention can be widely applied. It goes without sayingthat a circuit may be arranged in parallel which processes data in theconventional ECC block forms on the previous recording and reproducingapparatus with the result that the user can adopt any process form atthe time of recording data. In this case, in accordance with the ECCblock form selected at the time of recording the above ECC blockidentification information is automatically prepared so that theinformation is stored and arranged in a predetermined area.

A method for creating the PI series error-correcting code (or form)according to the present invention is not limited to the aboveembodiment.

FIG. 30 is a view showing another method for creating the PI serieserror-correcting word. In this example, there is shown a method forcreating 10 bytes code using these selected data by alternatelyselecting two-rows data every two columns. When the number of rows isthe even number, the PI series correcting capability can be heightenedeven when a part of one row data is damaged.

Furthermore, although the above explanation is centered upon therecording of the ECC block structure according to the present inventionon the recording medium, the present invention is not limited to theprocessing method and apparatus at the time of recording data on therecording medium. In the communication apparatus as well, data is formedinto packets so that data sectors are created. These data sector may beaggregated and subjected to modulation and is transmitted. In this case,it goes without saying that the form of the present invention may beadopted as the ECC block form in which the data sectors are aggregated.Furthermore, with respect to the modulation process method, the presentinvention is not limited to the above explanation. The data of the ECCblock is modulated with the QPSK method, the QAK method or the like.Furthermore, in the transmission channel, data may be sent by using theOFDM method.

Furthermore, in the above embodiment, a predetermined unit of the sectorset block is divided into the even number block and the odd-number blockso that an error-correcting words PO-a and PO-b are created. Theerror-correcting word may be is divided into two or more (Y) to createthe error-correcting word thereby constituting the PO series.

As has been explained above, when the present invention is used, theburst error-correcting capability can be largely improved with theredundant flag ratio which is the same as the conventional ratio in theerror-correcting method based on the byte data. Then, according to thepresent invention, the error-correcting process at an optical disk witha high density using a blue laser the development of which has juststarted can be realized to a physical error length larger than theconventional one.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An information recording method for recording information on arecording medium, the recording medium being able to have errorcorrection code (ECC) blocks arranged on the track, the ECC blocks beingobtained by using a plurality of sectors configured to includeinformation, the information recording method comprising; creating afirst PO creation block corresponding to one of the ECC blocks, thefirst PO creation block being configured by even-numbered rows ineven-numbered sectors and odd-numbered rows in odd-numbered sectors; andcreating a second PO creation block corresponding to an other one of theECC blocks, the second PO creation block being configured byodd-numbered rows in the even-numbered sectors and even-numbered rows inthe odd-numbered sectors.
 2. An information reproducing method forreproducing information from a recording medium, the recording mediumbeing able to have error correction code (ECC) blocks arranged on thetrack, the ECC blocks being obtained by using a plurality of sectorsconfigured to include information, one of the ECC blocks being createdby a first PO creation block, the first PO creation block beingconfigured by even-numbered rows in even-numbered sectors andodd-numbered rows in odd-numbered sectors, an other one of the ECCblocks being created by a second PO creation block, the second POcreation block being configured by odd-numbered rows in theeven-numbered sectors and even-numbered rows in the odd-numberedsectors, the information reproducing method comprising: reading the ECCblocks form the medium; and decoding the first and second PO creationblocks.
 3. An information reproducing apparatus for reproducinginformation from a recording medium, the recording medium being able tohave error correction code (ECC) blocks arranged on the track, the ECCblocks being obtained by using a plurality of sectors configured toinclude information, one of the ECC blocks being created by a first POcreation block, the first PO creation block being configured byeven-numbered rows in even-numbered sectors and odd-numbered rows inodd-numbered sectors, and an other one of the ECC blocks being createdby a second PO creation block, the second PO creation block beingconfigured by odd-numbered rows in the even-numbered sectors andeven-numbered rows in the odd-numbered sectors, the apparatuscomprising: a read device which reads the ECC blocks from the medium;and a decode device which decodes the first and second PO creationblocks.